GIS *G11 Flashcards
Geographic Information System
What is GIS *2
Collection of computer hardware and geographic data to analyse, manipulate and store geographic related data
Ways to obtain geographical data/DATA acquisition *min 4 max 7
*surveys
*maps
*stats
*aerial photographs
*satellite images
*GPS
*field work
Components of GIS *5
*hardware
*data
*software
*procedures
*trained people
What do points represent
Houses
Cities
Monuments
What do lines represent
Roads
Railways
Rivers
What to polygons represent
Shopping centres
Recreational areas
Golf course
How does GIS work
Tool to represent features in layers (thematic)
Thematic layers consist of *6
*real world
*land usage
*elevation
*parcels
*streets
*customers
Data types *2
Special
Attribute
What is special data *2
*Info linked to a specific location using coordinates
*Represented by points, lines, polygons, location and shape
What is attribute data *2
*Descriptive quality/characteristic
*Names, population, temperature, areas
Types of spread data *2
Vector
Raster
What is vector data *2
*Data that stores points, lines and polygons using XY coordinates
*aka discrete data
More detailed
What is raster data *3
*Data stored by grid using pixels
*does not represent individual features
*aka continuous data
What does data manipulation do *3
*change data to suite needs
*removes errors
*updates data sets
What does resolution refer to
How accurately location and shape of map can be depicted
What is the result of a higher amount in pixels *2
Higher resolution
Better image quality
Spacial analysis
Process of examining locations, attributes and relationships of features
Why is GIS better than raw data
Faster
More accurate
Improves management of resources
What is buffering
Creation of a zone around a feature
Measured in units of distance/time
Remote sensing
Observation of earth from a distance
OR
Taking a picture from a vertical distance of earth
How are digital images sent to a computer (remote sensing)
One pixel at a time
How is remote sensing stored in
Raster data
What tools can be used for remote sensing
Satellite
Drone
Helicopter
Benefits of remote sensing *4
*cover large areas
*consistent image quality
*allows change detection
*gain access to inaccessible areas
Problems with raw images *2
Distorted
Degraded
What does pre-processing do
Allows the correction of distorted images
